JPS59179545A - Reinforced styrene resin structure - Google Patents

Abstract

PURPOSE:To provide the titled easily producible composition consisting of a resin matrix, grafted rubber particles and a specific straight-chain styrene- butadiene block copolymer, and having remarkably excellent impact resistance and excellent appearance and heat resistance. CONSTITUTION:The objective composition is composed of (A) a styrene resin matrix, (B) grafted rubber particles having a weight-average particle diameter of 0.05-1 micron and dispersed in the matrix (A), and (C) dispersed particles of a straight-chain styrene-butadiene block copolymer forming large particles composed of a plurality of mutually connected particles (B) and a part of the component (A) included therein, and having a weight-average particle diameter of 0.1-5 microns. The component (A) is preferably the one consisting of 28- 69wt% of styrene, 25-45wt% of alpha-methylstyrene and 1-7wt% of acrylonitrile. 40-99pts.wt. of a copolymer obtained by dispersing 5-20wt% of the component (B) in the above component (A) is compounded with 1-10pts.wt. of the component (C) and 0-59pts.wt. of polystyrene, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a reinforced structure made of styrenic resin that has much better impact resistance than conventional styrene resins, has an excellent appearance, and is easy to manufacture, as well as a heat-resistant structure. This invention relates to a reinforced styrene resin structure with excellent properties.

A thermoplastic resin containing polystyrene as a continuous phase and diene rubber as a dispersed phase is known as high-impact polystyrene.
It is used in a wide range of applications because of its excellent properties such as appearance, processing fluidity, and dimensional accuracy. However, since the heat resistance is insufficient, there has been a desire for a resin that has the characteristics of impact-resistant polystyrene and has improved heat resistance. ABS resin is used for applications where the heat resistance of high-impact polystyrene is insufficient until now.
In particular, heat-resistant ABS resins and the like are often used. However, although the heat resistance of heat-resistant ABS resin has been improved,
On the other hand, there is a significant drop in processing fluidity, and high temperatures are required to mold thin-walled products or products with complex shapes, resulting in problems such as molding problems due to gas generation, for example. On the other hand, in order to improve the heat resistance of impact-resistant polystyrene, a copolymer consisting of α-methylstyrene and styrene was used as a conventional Blending with impact polystyrene is known. Such a modification method provides the same structure as high-impact polystyrene and higher heat resistance, but the impact resistance strength is not always sufficient and its applications are limited.

In view of the above, the present inventors have conducted intensive research to further improve the impact resistance of these resins with improved heat resistance. Among thermoplastic elastomers, the inventors have found that・When block copolymers coexist,
This copolymer connects several diene-based graft rubber particles, incorporates the particles and a portion of the matrix resin, and forms quite large particles as a whole, which are dispersed in the matrix. As a result, the heat resistance remains unchanged. It was found that impact resistance was significantly improved.

Furthermore, the styrene resin matrix has a weight average particle diameter of 00.
5 to 7 micron grafted rubber particles are dispersed,
When a linear styrene-tadiene block copolymer is made to coexist, a plurality of the graft rubber particles are connected to form large particles in which the particles and the IJ lux fat are incorporated. They also found that the balance between appearance and impact resistance was significantly improved.

Taking this discovery as an opportunity, the present inventors further extensively investigated styrene resins, and found that only diene-based graft rubber particles were present as small particles, large particles, or a mixture of small and large particles. Compared to any other styrene-based resin structure that is dispersed in a styrene-based resin structure, it contains small particles of diene-based graft rubber as well as large particles in which these small particles are wrapped in a linear styrene-butadiene block copolymer. It has been found that the styrene resin structure has significantly improved impact resistance and appearance. Note that a structure in which only a styrene-butadiene block copolymer is dispersed has poor impact resistance and appearance, and a structure in which a star type styrene-butadiene block copolymer, which is not a linear type, is used has poor impact resistance. It was also found that there was no improvement. The present invention has been made based on the above findings.

That is, the present invention provides a styrene resin matrix, graft rubber particles with a weight average particle diameter of 0.0 to -1 micron dispersed therein, and a plurality of the graft rubber particles connected to each other, so that the particles and the matrix are bonded together. Linear styrene-butadiene mainly forms large particles incorporating resin.
This invention relates to a reinforced styrenic resin structure composed of dispersed particles of a block copolymer having a weight average particle diameter of 0/- microns.

The reinforced styrenic resin structure of the present invention has the major features of being excellent in both impact resistance and appearance, and being extremely easy to manufacture.

The styrenic resin as the matrix resin in the present invention refers to a thermoplastic resin containing styrene as a constituent unit, such as polystyrene, styrene-acrylonitrile copolymer (AS resin), methacrylic acid derivative and styrene derivative as main components. Examples include copolymers (MS resins), styrene-α-methylstyrene copolymers, and poly-variamethylstyrene.

The above-mentioned styrene-α-methylstyrene copolymer is known as a heat-resistant resin, as described above, and as a very preferable form, the present invention uses 2 gN of styrene and 9% by weight of α-methylstyrene, Copolymer (
A) A straight-chain type in which the qo ~ 99 heavy part and a plurality of weight-grafted rubber particles are connected to form particles having a size of θ/-5 microns in which the particles and the matrix resin are incorporated. This invention relates to a reinforced styrenic resin structure with good heat resistance, which is made by blending 7 to 10 parts by weight of a styrene-butadiene block copolymer (B) and further 0 to 39 parts by weight of polystyrene or high-impact polystyrene. .

Furthermore, the present invention provides a styrene resin polymer consisting of 100 wt. and a plurality of the graft rubber particles are connected to each other and the particles and the matrix resin are incorporated therein. / N & mikutylene-butadiene block copolymer (B) /~/θ parts by weight and further 0 to 39 parts by weight of polystyrene or high-impact polystyrene are blended to form a reinforced styrenic resin structure. .

In the present invention, graft rubber particles are rubber particles obtained by graft polymerizing styrene, α-methylstyrene, acrylonitrile, methyl methacrylate, etc. to polybutadiene rubber containing butadiene as a main component, suf-v-butadiene rubber, etc. , its size is 005 to 1 in terms of weight average particle diameter.
I'm talking about microns. In the case of particles smaller than 0.005 microns in size, linear styrene-butadiene block copolymer (hereinafter simply referred to as SB block copolymer)
Even if added, the impact resistance of the resin before addition is so low that it has no practical meaning, and if it is larger than 7 microns, the appearance of the resin molded product will be significantly impaired, which is not preferable. A more preferable particle size is 0.1 NO,! i micron.

In the present invention, the particles formed by the SB block copolymer have a structure in which one or more/θθ or less graft particles are wrapped, and the size thereof is 07 to 3 microns.

In the present invention, the linear styrene-butadiene block copolymer has the general formula (AB+rlA (n is /-/
)) or (A-B)rn (m is co-s) (where A is a styrene block and B is a butadiene block).

A particularly important point in the structure of the present invention is that diene-based graft rubber particles having a particle diameter of θ0~/, preferably 07 to 03 microns, and a styrene-butadiene block copolymer having a unique particle morphology are used. As a result, the striking strength was dramatically improved. As is clear from the electron micrograph in Figure 1 of the attached drawings, the styrene-butadiene block copolymer connects the small particles of graft rubber and forms considerably large particles with the graft rubber particles and matrix resin inside. It was discovered that the particles were dispersed in a matrix, forming a unique form that had not been previously known.

Such a unique structure and its effects can be considered when the matrix resin is polystyrene, but it can also be considered in other cases, but the matrix resin is the aforementioned styrene, α-methyl, which has high heat resistance but somewhat poor impact resistance. It is particularly effective in improving the impact resistance of heat-resistant resins made of styrene.

Furthermore, a secondary effect of the presence of the linear styrene-butadiene block copolymer is that polystyrene can be easily blended with the heat-resistant resin. Journal of Polymer Science (
Journal of Polymer Science
) B 3, page 1007 (/9 A,!i), when the difference in acrylonitrile content exceeds q da in two types of styrene-acrylonitrile copolymers, the compatibility decreases; If the acrylonitrile content in the copolymer is 7 weight meters or less due to the coexistence of the copolymer, the compatibility with polystyrene will not decrease.

Therefore, blending of polystyrene or high-impact polystyrene with the heat-resistant resin becomes easy.

In the reinforced styrene resin structure of the present invention, the content of the dispersed graft rubber particles is required to be 3 to 20% by weight based on the matrix resin, and the particle size thereof is 0.05 to 7 microns, preferably 0.7 to aS. It is micron. If the S content is less than 20% by weight, the impact strength of the composition will be low, and if it exceeds 20% by weight, a good appearance cannot be obtained.

The average particle diameter was determined by taking an electron micrograph using an ultrathin section method and weight-averaging the measured particle diameters.

The content of linear styrene-butadiene block copolymer should be between 7 and 70% by weight.

If it is less than 7% by weight, no effect of improving impact resistance will be exhibited, and if it is more than io% by weight, a good appearance cannot be obtained.

In the reinforced styrenic resin structure with good heat resistance of the present invention,
If the amount of α-methylstyrene in the copolymer (A) is less than 2% by weight, sufficient heat resistance cannot be obtained, and if it exceeds aS weight%, not only the impact strength but also the fluidity will decrease. Furthermore, if the acrylonitrile content is less than 7% by weight, thermal stability and impact strength will decrease, and if it exceeds 7% by weight, ink and processing fluidity will decrease. In addition, if the content of copolymer CA) in the composition is less than yo weight part, sufficient heat resistance cannot be obtained, and if it exceeds weight part of cotton, the content of copolymer CA) will deteriorate with the styrene-butadiene pro-link copolymer (B). No synergistic effect can be obtained. On the other hand, styrene
If the content of the 7-lydiene block copolymer (B) is less than 1 part by weight, the impact strength will not be improved, and if it is more than 70 parts by weight, the heat resistance will decrease. If the content of polystyrene or impact-resistant polystyrene (C) exceeds 59 parts by weight, sufficient heat resistance cannot be obtained.

In addition, if the content of (copolymer) in the reinforced styrenic resin structure of the present invention is less than 1 part by weight, a good balance between appearance and impact resistance cannot be obtained; If it exceeds the amount, a synergistic effect with the styrene-pucdiene block copolymer (B) cannot be obtained. On the other hand, if the styrene-butadiene block copolymer (B) is less than 7 parts by weight, the impact strength will not be improved, and if it is more than 70 parts by weight, a good appearance cannot be obtained. If the content of polystyrene or impact-resistant polystyrene (0) exceeds 39 parts by weight, a good balance between appearance and impact resistance cannot be obtained.

Copolymers (A) and (b) can be produced by emulsion polymerization, bulk polymerization, or suspension polymerization, and emulsion polymerization is particularly preferred. Further, as a method for producing the copolymer (B), for example, Japanese Patent Publication No. 34-19.2. GL, the block copolymerization method proposed in the publication, that is, a method in which styrene or butadiene or a styrene-butadiene mixture is polymerized stepwise in a hydrocarbon solvent using an organolithium compound as an initiator. , but not limited to these. Furthermore, polystyrene or high-impact polystyrene (
C) can be obtained by one or a combination of emulsion polymerization, bulk polymerization, and suspension polymerization.

Examples of the method for producing the reinforced styrenic resin structure of the present invention include a method of blending the copolymer of (1) or (to) and (B) with the resin of (0). Any method that can be used may be used.If necessary, it is possible to add antioxidants, ultraviolet absorbers, flame retardants, pigments, glass fibers, plasticizers, etc., and it is also possible to make it into a solid form using an extruder, etc. can.

As described above, the present invention relates to a reinforced styrenic resin structure made of styrene resin, which has significantly better impact resistance than conventional styrene resins, has an excellent appearance, and is easy to manufacture. Due to its excellent heat resistance, impact strength, processing fluidity, etc., it is expected to be used in a wide range of fields such as automobile parts, industrial parts, and home appliance parts.

This will be explained below using examples.

Example/ The inside of a reactor equipped with a stirrer was replaced with nitrogen, and a butadiene copolymer latex consisting of 200 parts by weight of ion-exchanged water, 10% by weight of styrene, and 90% by weight of butadiene (
70 parts by weight of solids (weight average particle diameter 02 μ) and 70 parts by weight of disproportionated potassium rosin acid were added and the temperature was raised to go''c. From the time the temperature inside the reactor reached gO℃, the weight of acrylonitrile S was increased. %, α-methylstyrene 110 wt%, styrene SS wt% qo parts by weight and 0.2 parts by weight of tertiary dodecyl mercaptan were added over 5 hours, and potassium persulfate was added in parallel with the monomers. An aqueous solution consisting of 1 part by weight of θ and 50 parts by weight of ion-exchanged water was continuously supplied to the reactor over S time.

After the supply was completed, the polymerization reaction was further continued for 2 hours at go”c,
Polymerization was completed. The polymerization rate was determined by measuring the solid content of the polymerized latex (based on the monomer supplied), and it was 9g.
%Met. The obtained latex was dropped into a 2% aqueous aluminum sulfate solution and coagulated. After further dehydration and drying, 4/, p'-butylidene bis(3-methyl-6
- tertiary butylphenol) tto, s wt % was added, and a pelletized copolymer (A) was obtained using a vented screw extruder. Copolymer (A) and (AB)
It is represented by the general formula 2 and contains styrene, t% by weight
The styrene/-butadiene block copolymers were blended in the proportions shown in Table 1 using a vented screw extruder, and then injection molded to prepare specified test pieces. Table 1 shows the results of measuring physical properties using the prepared test pieces.

Note that general impact-resistant polystyrene is also listed in Table 2 as a comparative example.

From the results in Table 1, it can be seen that the reinforced styrenic resin structure according to the present invention has an excellent balance of heat resistance, impact strength, and processing fluidity.

Table / *■ (A B) A styrene-tadiene block copolymer containing 0% by weight of R and represented by the general formula of 2.

■ 'l5OR//33 ■ J I S KAg7/ ■ Falling weight impact strength is the SO% of the test piece (flat plate) used when an impact is applied to a flat plate with a thickness of Jffllll with a falling weight at a constant speed. Expressed in terms of the energy required to destroy it.

■ JIS K1. g7/ Example copolymer (A) obtained in Example 1 was added with styrene containing 70% by weight of styrene represented by the general formula (AH)2.
Tutadiene block copolymer, (A B) 4X (in the formula, B is a block consisting essentially of a conjugated diolefin polymer, A is a block consisting essentially of a monovinyl-substituted aromatic compound polymer, and X is a block consisting of a monovinyl-substituted aromatic compound polymer; polyfunctional residue with a bond of
A styrene-butadiene block copolymer with a styrene content of 30% by weight represented by the general formula, high-impact polystyrene modified with 6% by weight of diene rubber, and /% by weight of diene rubber. The resulting high-impact polystyrene was mixed in the proportions shown in Table 1, and a resin pellet was obtained using a vented screw extruder. Next, predetermined test pieces were made from the obtained resin using an injection molding machine, and the physical properties were measured. The results are shown in Table 2.

From the results in Table 1, it can be seen that the reinforced styrenic resin structure according to the present invention has an excellent balance of heat resistance, impact strength, and processing fluidity.

Example 3 The inside of a reactor equipped with a stirrer was replaced with nitrogen, and 2SO parts by weight of ion-exchanged water, 0% by weight of methi 2fufu, and butadiene were added.
70 parts by weight of a butadiene copolymer latex (weight average particle size: 02 μm) consisting of 90 diaphragms (in terms of solid content) and parts by weight of disproportionated potassium rosinate/S were added, and the temperature was raised to 75"C. Inside the reactor 90 parts by weight of styrene monomer was added for 3 hours from the time when the temperature of
Parts by weight of the aqueous solution were continuously fed into the reactor over a period of 3 hours. Will it be returned after the supply ends? The polymerization reaction was continued at 5'C for 2 hours to complete the polymerization. The polymerization rate was determined by measuring the solid content of the polymerized latex (relative to the supplied moamer) and was found to be 100%.

The obtained latex was dropped into a % aluminum sulfate aqueous solution and coagulated. After further dehydration and drying, +, <
% of z'-butylidene bis(3-methyl-tert-butylphenol) was added, and a copolymer in the form of pellets was obtained using a vented screw extruder. A styrene-butadiene block copolymer with a styrene content of 1 Ioz expressed by the general formula of copolymer) and (AB)2, and (AB)4X (where B is substantially a conjugated diolefin). A block consisting of a polymer, A is a block consisting essentially of a monovinyl-substituted aromatic compound polymer, X
After blending a styrene-butadiene block copolymer with a styrene content of 3θ weight% expressed by the general formula of a polyfunctional residue with 3 bonding hands in the proportions shown in Table 3 using a vented screw extruder. A predetermined test piece was prepared by injection molding.

Table 3 shows the results of measuring physical properties using the prepared test pieces.

From the results in Table 3, it can be seen that the reinforced styrenic resin structure according to the present invention has excellent impact strength and appearance.

(Margins below) G8 (A) (%1 = ψ8/ψo8×100 Example DA The copolymer (2) obtained in Example 3 contained a styrene-containing fjkqO weight expressed by the general formula (AB)2. % of styrene-butadiene block copolymer, (A-B)
4X (in the formula, B is a block substantially consisting of a conjugated diolefin polymer, A is a block substantially consisting of a monovinyl-substituted aromatic compound polymer, and X is a polyfunctional residue having 9 bonds) A styrene-butadiene block copolymer having a styrene content of 30% by weight and having a weight average particle diameter of ? ,/μ, high-impact polystyrene modified with 6% by weight of diene rubber, weight average particle size l/μ
Impact resistant polystyrene modified with a diene rubber with a weight average particle diameter of 31 I-μ and a weight i% of an impact resistant polystyrene modified with a diene rubber in the proportions shown in Table q. The mixture was mixed in a vented screw extruder to obtain pelletized resin. Next, predetermined test pieces were made from the obtained resin using an injection molding machine, physical properties were measured, and the results were shown in the table.

The results of the table show that the reinforced styrenic resin structure according to the present invention has excellent impact strength and appearance.

(Margin below)

[Brief explanation of drawings]

FIG. 1 is an electron micrograph (magnification: vrooo) showing the internal structure of seven examples of reinforced styrene resin structures of the present invention. FIG. 2 is a micrograph (magnification: 500) showing the internal structure of conventional high-impact polystyrene. Patent applicant: Asahi Kasei Industries, Ltd.

Claims (3)

[Claims] (1) A styrene resin matrix, glazed rubber particles with a weight average particle diameter of 0.5 to 7 microns dispersed therein, and a plurality of glazed rubber particles are connected to each other, and the particles and the matrix resin are connected to each other. A reinforced styrenic resin structure composed of dispersed particles having a weight average particle diameter of 0/~t microns and made of a linear styrene-butadiene block copolymer mainly forming large particles in the incorporated form. (2), styrene 2g-AqTRi%, α-methylstyrene, 25~lI left weight%, and acrylonitrile 7~
fif in a styrenic resin matrix consisting of 7% by weight.
It average particle diameter OO5~/70~2 of copolymer (A) dispersed by S~20% weight of grafted rubber particles of Miku-Shin
9 parts by weight, and 07- in the form of connecting a plurality of the graft rubber particles and incorporating the particles and matrix resin therein.
Linear styrene-butadiene block copolymer (B) 7 to 70 mainly forming particles of S micron size
A reinforced styrenic flank structure with good heat resistance, which is made by blending 0 parts by weight of polystyrene or impact-resistant polystyrene. (3) of a polymer in which -20% by weight of grafted rubber particles with a weight average particle diameter of 0.3 to 7 microns are dispersed in a styrene resin matrix consisting of styrene/θO
0 to qq parts by weight of the grafted rubber particles, and linear styrene mainly forming particles with a size of 07 to 5 microns in which a plurality of the graft rubber particles are incorporated and the particles and the matrix resin are incorporated. Butadiene block copolymer (B
) 7 to 70 parts by weight and further 0 to 9 parts by weight of polystyrene or high-impact polystyrene.